Hazard Rating with TRAQ

TRAQ — the Tree Risk Assessment Qualification — is the ISA's standardized framework for evaluating tree risk. If you're delivering risk assessments to insurers, municipalities, or commercial clients, TRAQ is the language they expect. This page is the working summary; for the formal credential, take the ISA TRAQ course.

Quick Start

• TRAQ defines three assessment levels: limited visual (1), basic (2), and advanced (3). Pick the level the client paid for.
• Risk = likelihood of failure × likelihood of impact × consequences. Each is rated on a defined scale.
• The combined output is one of four risk ratings: Low, Moderate, High, or Extreme.
• Document the target zone, the defects, the assumptions. The risk rating is meaningless without the evidence behind it.

The three levels

1. Level 1 — Limited visual

   A walking or drive-by inspection. You're looking for obvious defects from the ground. Useful for screening large populations (a city's street trees, a campus's specimen trees) before deciding which need closer inspection.

   Reports at Level 1 should be explicit that the assessment is screening-only — clients sometimes mistake Level 1 for a defensible expert opinion.

2. Level 2 — Basic

   The most common engagement. A 360-degree walk-around, ground-based inspection of the trunk, root crown, and visible canopy. Use of basic tools (DBH tape, mallet for sounding, probe for cavities). Document with photos.

   Most residential and commercial property assessments are Level 2.

3. Level 3 — Advanced

   Diagnostic tools beyond visual: aerial inspection (climbing or bucket truck), sonic tomography, resistograph, root crown excavation, soil testing.

   Level 3 is for high-value or high-target trees where Level 2 found a concerning defect that needs quantification.

The risk matrix

TRAQ rates risk as the product of three factors:

Likelihood of failure — how likely is the tree (or part of the tree) to fail within the inspection interval? Rated Improbable / Possible / Probable / Imminent.

Likelihood of impact — given a failure, how likely is it to hit something or someone? Rated Very Low / Low / Medium / High.

Consequences — if it hits, how bad is the outcome? Rated Negligible / Minor / Significant / Severe.

The combined output collapses into one of four risk ratings:

• Low — acceptable, monitor at next inspection cycle.
• Moderate — mitigation recommended (pruning, cabling, target removal).
• High — mitigation strongly recommended on a defined timeline.
• Extreme — immediate action; tree should be made safe within days.

Targets

A "target" is a person or property within striking distance of a potential failure. Common targets:

• Constant — buildings, roads, parking, occupied spaces. Always within range.
• Frequent — sidewalks, paths, regularly used yards.
• Occasional — outbuildings, side yards, woodlots with seasonal access.
• Rare — far corners of large properties, uninhabited natural areas.

A massive co-dominant failure over a parking lot is a different rating than the same defect over a back-corner woodlot. Document the target zone — clients who don't see "target" called out often dispute the recommendation.

Defects to flag

The ones that drive most ratings:

• Co-dominant stems with included bark — the union is structurally weak; included bark prevents the stems from grafting together. High failure likelihood under wind load.
• Decay (cavities, conks, basal cracks) — sound-test with a mallet. Cavities >40% of the cross-section are a strong concern.
• Root issues (girdling, decay, severance) — root flare absence, fungal conks at the base, or recent excavation/grading nearby.
• Lean — recent lean (soil heave, root tearing) is critical; long-standing lean is usually stable.
• Deadwood — proportion and size; large deadwood (>4 inch diameter) over targets is a removal candidate even on otherwise healthy trees.
• Cracks — radial cracks down the trunk are major. Bark cracks are usually superficial.
• Cankers / cracks at unions — failure points in storms.

Assessment intervals

Recommend a re-inspection interval based on the rating:

| Rating | Typical interval | |---|---| | Low | 3-5 years | | Moderate | 1-3 years | | High | 6-12 months | | Extreme | Make safe immediately |

Adjust for tree species (fast-decay species like willow, silver maple shorten the interval), site conditions, and recent storm history.

Common Questions

Do I need TRAQ certification to do risk assessments? Not legally in most jurisdictions, but insurers and municipalities increasingly require it. The ISA TRAQ course is the recognized credential.

How do I document the assessment in Tree Inventory AI? Capture the tree, mark the defects (defect chips on the tree detail), photograph with markup pointing at each defect, add the target zone in the notes field, and set the recommendation. The PDF report assembles all of this into a per-tree page.

What about ANSI A300? ANSI A300 is the pruning + management standards reference; TRAQ is the risk assessment framework. They're complementary. See Pruning Best Practices.

Is the AI's "condition" rating a TRAQ rating? No. The AI's condition is a general health rating (Good / Fair / Poor / Dead). TRAQ risk requires a human assessor — the AI is a starting point that flags candidates for closer inspection.

Related

• Pruning Best Practices — what to do once you've identified a defect that pruning can mitigate
• Capturing Trees — how to document a TRAQ assessment in the app
• Photos and Markup — markup conventions for risk assessment photos